Solvent extraction of dripolene fractions to yield polymerizable aromatic monomer mixtures



United States Patent M SOLVENT EXTRACTION OF DRIPOLENE FRAC- TIONS TOYIELD POLYMERIZABLE AROMATIC MONOMER MIXTURES Frank Scardiglia,Arlington Heights, and Takeo Hokama,

Chicago, IlL, assignors to Velsicol Chemical Corporation, Chicago, 311.,a corporation of Illinois No Drawing. Filed Nov. 16, 1966, Ser. No.594,685

Int. Cl. (308i /42, 19/00 US. Cl. 26082 13 Claims ABSTRACT OF THEDISCLOSURE A process for the recovery of dicyclopentadiene and theproduction of resinous products from a feed stream containing from about5 to about 50 weight percent of dicyclopentadiene and from about 5 toabout 50 weight percent of aromatic olefins which comprises contactingsaid stream with dimethyl sulfoxide and an aliphatic sol vent having aboiling point less than 140 C., recovering the dicyclopentadiene fromthe aliphatic solvent and polymerizing the aromatic olefin traction intoresinous product.

This invention relates to the fractional liquid extraction ofdicyclopentadiene from a stream containing a multiplicity of aromaticolefinic compounds. In particular this invention relates to anextraction using dimethyl sulfoxide and an aliphatic solvent to recoverhigh percentages of the available dicyclopentadiene and to furtherobtain an aromatic olefinic fraction useful in the production ofresinous products.

In the past a variety of procedures have been proposed and used torecover dicyclopentadiene from streams also containing aromatic olefins.These procedures essentially involve a variety of distillation and/orheat treatments.

One known procedure involves heating the feed stream in the vapor stateto a substantial temperature so as to dedimerize the dicyclopentadienefollowed by further distillation of the product to recover thecyclopentadiene. Unfortunately this procedure allows for a normalrecovery of the available dicylopentadience of about 70%. Not only doesthis procedure result in a loss of substantial quantities of availabledicyclopentadiene but it also results in a byproduct stream containingpolymeric products, dicyclopentadiene and other contaminates interferingwith the quality of resinous products prepared therefrom.

A second available procedure is by distillation of the stream. Thisprocedure is not practical due to the similarity of the boiling pointsof the various components, i.e. dicyclopentadiene, methyl styrene,styrene, vinyl toluene and indene. It is further complicated by theequilibrium between cyclopentadiene and dicyclopentadiene.

It is therefore an object of the present process to devise a process forthe recovery of dicyclopentadiene, particularly from streams containingaromatic olefins.

An additional object of the present invention is to devise a process forthe recovery of the maximum amount of the available dicyclopentadienefrom dripolene derived streams.

3,485,807 Patented Dec. 23, 1969 ICC Still another object of the presentinvention is the substantial removal of dicyclopentadiene from streamscontaining polymerizable aromatic compounds.

Still another object of the present invention is the preparation ofimproved resinous products from aromatic olefins from streams alsocontaining dicyclopentadiene.

Other objects of the present invention will become apparent from theensuing description.

It has now been found that there can be recovered from streamscontaining from about 5 to about 50 weight percent dicyclopentadiene andfrom about 5 to about 50 weight percent aromatic olefinic compounds aminimum of weight percent of the dicyclopentadiene present in thestream. By the present process utilizing dimethyl sulfoxide (DMSO) andan aliphatic solvent having a boiling point of less than C. there isalso obtained a desirable aromatic olefin traction. Not only does thispermit maximum utilization of the dicyclopentadiene available in thefeed stream, it also provides a mixture of aromatic olefinssubstantially free of dicyclopentadiene and useful for a variety ofpurposes, particularly in the production of resinous products by thermaland catalytic procedures.

Dimethyl sulfoxide has been noted in the literature to have utility incertain specific extraction operations.

United States Patent No. 2,365,898 broadly discloses the use ofsulfoxides in general in solvent extraction processes.

United States Patent No. 3,005,032 discloses that it can be used forseparating naphthalenic hydrocarbons from non-naphthalenic aromatichydrocarbons.

In an article in Chemical Week, Jan. 15, 1955, pp. 6264 variousproperties of dimethyl sulfoxide are discussed. This article states thatas a solvent it has a high capacity for aromatics, sulfur-containinghydrocarbons, but small afiinity for parafiins. An article in Chemicaland Engineering News, Oct. 5, 1964, pp. 50-51 reports the utilization ofdimethyl sulfoxide to separate aromatics from other hydrocarbon groups.See also Hydrocarbon Processing, vol. 45, No. 5 (1966), pp. 188192.

It has now been determined that dimethyl sulfoxide can be used toseparate and recover dicyclopentadiene from a feed stream containingaromatic olefins. In addition to providing an economic procedure forobtaining dicyclopentadiene, this process provides an olefinic productsubstantially free of dicyclopentadiene.

In essence this present process comprises contacting a feed streamcontaining from about 5 to about 50 weight percent dicyclopentadiene andfrom about 5 to about 50 weight percent aromatic olefins with dimethylsulfoxide and aliphatic compounds having a boiling point of less thanabout 140 C. This process permits the ready recovery of thedicyclopentadiene from the aliphatic solvent phase, whereas the aromaticolefins are recoverable from the dimethyl sulfoxide.

Dicyclopentadiene recovery of a minimum of 95 weight percent of thatavailable in the feed streams is readily obtained. Normally thisrecovery will be from about 97 to 99 weight percent of the availabledicyclopentadiene.

Similarly the dimethyl sulfoxide will contain a minimum of 90 percent byweight of the aromatic olefins available in the feed. Of particularvalue is the substantial absence of dicyclopentadiene in this mixture;the dicyclopentadiene content being a maximum of about 3 percent byweight of the extracted compounds. This permits the production ofdesirable resinous products not previously attainable from this feedstream by the other known procedures for the removal and recovery ofdicyclopentadiene.

This process can be performed by using standard operating procedures forliquid-liquid extractions, particularly for fractional liquidextractions with two solvents. This extraction can be convenientlyperformed in a countercurrent extraction column. In the column the feedenters in the center of the column whereas the respective solvents enterat opposite ends and flow counter to each other. The number of stages inthe extraction column must be determined for each system.

The feed stream for the present process can be obtained from varioussources. It can contain a multiplicity of components without interferingwith the operation of the process. One principal source for this type offeed stream are the dripolenes, obtained from the high temperaturepyrolysis of normally gaseous hydrocarbons. United States Letters PatentNos. 2,798,866 and 2,798,867 describe dripolenes and state typicalproperties and composition. This dripolene fraction is then preferablysubjected to distillation so as to remove substantially all of thetoluene and components boiling lower than toluene.

Other sources of feed streams of the above description can be used inthis process provided that they have the dicyclopentadiene and aromaticolefin content. The source of the feed will not affect the operation ofthe process.

It has been found that advantage can be had by incorporating minoramounts of water into the dimethyl sulfoxide. Varying amounts of watercan be used. Amounts of water of from about 2 to about volume percent ofthe dimethyl sulfoxide are of value.

The ratio of solvents and feed useful for the successful operation willvary with the actual composition of the feed, identity of the aliphaticsolvent, efiiciency of the extraction equipment and the other variablesof the process. It has been found that volume ratios of aqueous dimethylsulfoxide to the feed stream of between about 1:1 and 10:1 can be used.The use of additional solvent will not materially impair the extractionbut it will lower the capacity of the extraction equipment and the finalrecovery equipment. Similarly volume ratios of the aliphatic solvent tothe feed stream of between about 04:1 and 10:1 can be used. While theuse of additional quantities of solvent is not necessary it does notadversely affect the operation of the present process.

The aliphatic solvents useful in the present process can be substitutedor unsubstituted, a single compound or a mixture of compounds providedthat it has a boiling point below about 140 C. Since there is no need touse substituted aliphatic compounds for this purpose, the paraffins suchas heptanes, hexanes and pentanes are preferred due to theiravailability, low cost and solubility characteristics. Other aliphaticcompounds, including branched, cyclic and alkylcyclie compounds andmixtures thereof, having boiling points lower than about 140 C., such ascyclopentane, cyclohexane, methyl cyclopentane, etc. can be used.

Oneof the advantages of the present process is that it can be readilyused at ambient temperatures. While elevated temperatures can be used,there is no need to do so and therefore it is preferred not to useelevated temperatures.

Upon the completion of the extraction the dicyclopentadiene can berecovered from the aliphatic hydrocarbons by known procedures. Thiscould consist of removing the aliphatic solvents by distillationfollowed by thermal treatment of the bottoms at a temperature betweenabout 150 C. and about 400 C. to dedimerize the dicyclopentadiene to thecyclopentadiene monomer which is recovered as an o e h ad f ac ion.Eric; 9 e wa 9 .4 the aliphatic solvent the dicyclopentadiene solutioncan be washed with water to remove traces of dimethyl sulfoxide. Thealiphatic solvent can then be recycled for use in the extraction. Thedimethyl sulfoxide can be separated from the aromatic olefins byextraction with water. The dimethyl sulfoxide is recycled afterconcentration for further use in the extraction process and the aromaticolefin fraction can be used in the preparation of excellent resinproducts as will be described subsequently.

The following examples illustrate the performance of the presentextraction process but the present process is not limited thereto.

In the extractions set forth in these examples, an 18 stageYork-Scheibel counter-current extraction unit was used. Hexane was usedas the aliphatic solvent and entered the extraction unit below the firststage and was removed from the column at a point above the 18th stage.The dimethyl sulfoxide was pumped into the unit at a point above the18th stage and removed at a point below the first stage. The feed streamin each instance was obtained by distillation of a dripolene tosubstantially remove the toluene and all components having a boilingpoint lower than toluene. The feed content as analyzed by gaschromatographic analyses in weight percent was as follows:

Cyclopentadiene 27.7 Methyl cyclopentadiene 4.5 Toluene 2.8 Nonaromatics (C C 08 Ethyl benzene 1.7 Xylenes 2.6 Propyl benzene l.-lStyrene 14.8 Methyl ethyl benzene 0.8 Methyl styrene 0.8 Unknown 0.4Vinyl toluene l.6 Indene 4.8

Unknown 3.1 Naphthalene 5.9 Compounds boiling higher than naphthalene27.3

The material balance for Examples 1-5 were as follows:

Dimethyl- Hexane Hexane DMS 0 Feed sulfoxide In solution solutionExample (grams) In (grams) (grams) Out Out In Examples 1 and 2, thedimethyl sulfoxide contained 7 Weight percent water, whereas in Examples3-5 the dimethyl sulfoxide contained 5 weight percent Water. The hexanesolution was recovered from the top of the extraction column and thehexane removed by distillation through a bubble cap distillation columnat 100 C. pot temperature and an initial pressure of 750 mm. Hg and afinal pressure 300 mm. Hg. The concentrate was analyzed by gaschromatography. The dimethyl sulfoxide solution was recovered from thebottom of the extraction column, diluted with water and extracted withbenzene. e benz ne ay as pa a d f om th q eous pha e obtained from theextraction after removal of the dimethyl sulfoxide by distillation canbe used in the Example 1 Example 2 Example 3 Example 4 Example 5 DMSOHexane DMSO Hexane DMSO Hexane DMSO Ilexane DMSO Hexane Fraction,Fraction, Fraction, Fraction, Fraction, Fraction, Fraction, Fraction,Fraction, Fraction, Weight Weight Weight Weight Weight Weight WeightWeight Weight Weight; percent percent percent percent percent percentpercent percent percent percent and analyzed by gas chromatography. Theresults of the gas chromatographic analysis are as follows:

Component 698079111501443 HQL LZZ5LQLLLZO 508095372197083 AMLLOLLZQQ 1 3010 1 1 518065183046023 9 0 1 LZ2 &4 004 120 1 1 413048340103450 TaO 0 01 L0 Q 005 00606504301535- 3 12 MQLQZZZQ 022044972492603 4 7 L LZL MLQLLQWU 3 720064 19502 1 LZLA QQLLQALO preparation of the resinousproducts. In the alternative a concentrate of one or several selectedaromatic olefins ht can be used. In the case of the dripolene derivedfeed percent of the available amounts of each component in 29 streams,concentrates containing major amounts of styrene the feed: or indenerovide excellent resin formers.

Example 3 Example 4 Example 5 Hexane DMSO Hexane DMSO Hcxane DMSO HexaneFraction Fraction Fraction Fraction Fraction Fraction Fraction Example 1Example 2 DMSO Hexane DMSO Fraction Fraction Fraction than naphthalene.Weight (grams) i The following table based on the foregoing facts showsthe distribution of aromatic olefins and cyclopentadiene Compoundsboiling higher in the hexane and dimethyl sulfoxide streams in weComponent .505 wane 208 A m E Cyclopentadieno...

In each of these instances it has been found that the aromatic olefinsobtained by the extraction process have properties, particularlysuperior stability to oxidation e/feed/hexane and ultraviolet light,color and softening point. It further ratio of 6/2/1 as per Example 4.The analysis of compermits control of the polymerization reaction so asto ponents in and out of the system by gas chromatographic obtainresinous products having the requisite properties. analysis was asfollows: The thermal polymerizations can be performed by heating thearomatic olefins to a suitable polymerization tem- 45 perature. Thistemperature will vary with the identity 2 of the feed, thepolymerization time and the requisite ractionproperties of the finalproduct. Polymerization tempera- In order to confirm the above resultsan extraction, Example 6, was performed using the previously described gthe total time of the extraction Dimethyl sulfoxide Feed fraction 1Polymerizable olefins procedures but increasin to 32 hours, using adimethyl sulfoxid Component tures between about 120 and 300 C. areuseful, with temperatures between about 150 and 250 C. being preferre'd.The polymerization may be carried out in the presence of an inertsolvent. Useful solvents include aromatic solvents, such as benzene,toluene, etc. and aliphatic solvents such as pentane and hexane.

In the preparation of catalytic polymers a variet of catalysts can beused. In particular, Friedel-Crafts catalysts, such as borontrifluoride, aluminum chloride,

ethyl aluminum dichloride, and aluminum brom free radical catalysts,such as benzoyl p 49059088499701 vwJALLLZZQQQQQfl MO 58755464793000 L 2L2 L4 L 4 000 425 (lien ide and eroxide, azobisisobutyronitrile anddi-t-butyl peroxide are useful. The amount of catalyst will vary withits identity, the composition of the feed, the polymerization time andthe requisite properties of the resinous products. Normally the catalystis present in amounts from about 0.1 to 5 weight percent of thepolymerizable components of the and methyl cyclopentadiene. The latterprocedure is more food. Additional amounts of catalyst can be used.

The polymerization time will vary similarly. Normal polymerization timesof from about 0.5 to 6 hours are useful. The polymerization temperaturewill also vary and normally will be lower than in the production of Aparticular advantage of the present extraction process thermal resins.Temperatures between about 0 C. and

150 C. are satisfactory.

The following examples illustrate the preparation of resinous productsfrom the aromatic olefin fraction obtained from the present extractionprocess after removal In these polymerizations, the aromatic olefinfraction of the dimethyl sulfoxide.

naphthalene.

38.4 weight percent of the feed.

1 61 weight percent of feed.

The cyclopentadiene and methyl cyclopentadiene can be readily recoveredfrom the hexane fraction either by distillation under reduced pressuresor by thermal cracking of the dimers and recovering the cyclopentadieneefiicient permitting recovery of about weight percent of the availablecompounds into a fraction containing a minimum of about 92 weightpercent cyclopentadiene and methyl cyclopentadiene.

is the availability of an aromatic olefin fraction useful in thepreparation by conventional thermal or catalytic procedures of resinousproducts having desirable properties.

7 EXAMPLE 7 Thermal polymerization of aromatic olefin fraction A glassreaction flask was equipped with a gas inlet tube, stirrer, thermometerand reflux condenser. A solution of the aromatic olefin fraction ofExample 6 after removal of the dimethyl sulfoxide and hexane (300 grams)was placed in the reaction flask and cooled to 10 C. Boron trifluoridewas introduced into the reaction flask through the gas inlet tube untilthe solution was saturated. It constituted 0.23 weight percent of thefeed. The temperature of the reaction mixture was maintained betweenabout 10 C. and 40 C. After two hours of reaction time, toluene (200ml.) was added to the mixture. The mixture was then filtered throughflorex clay and the filtrate distilled to a pot temperature of 525 F. at10 mm. Hg. The resin product, obtained therefrom (213 grams)representing a 70.7% yield, had the following properties:

Softening point, F. 302 Gardner color Ca. 2 Armstrong cloud point, C.139 Molecular weight Ca. 14,000 Mixed aniline point, C. 59.2 Iodine No.9.8 Oxygen absorption Ultra violet stability 24 hours 27.2

EXAMPLE 8 Polymerization of a styrene concentrate The aromatic olefinconcentrate of Example 6 was washed with water and fractionated underreduced pressure. A styrene fraction having a boiling point of 62-66 C.at 50 mm. Hg and containing from 90-96 weight percent styrene and theremainder xylenes and alkyl benzenes (9.1 grams), was placed in astainless steel tube. The tube was flushed with nitrogen, sealed andplaced in a constant temperature bath maintained at 175 C. for 3 /2hours. The resinous product was dissolved in toluene (50 ml.), and theproduct concentrated at a temperature of 60-70 C. at 20 mm. Hg theresinous product (7.6 grams, an 82 percent conversion) was a waterwhite, clear resin having a molecular weight of approximately 50,000.

EXAMPLE 9 Polymerization of a styrene concentrate The aromatic olefinconcentrate of Example 6 was Washed with water and fractionated underreduced pressure. Di-t-butyl peroxide (0.1 gram) was added to a styrenefraction having a boiling point of 62-66 C. at 50 mm. Hg and containingfrom 90-96 percent styrene and the remainder xylenes and alkyl benzenes(9.2 grams), and placed in a stainless steel tube. The tube was flushedwith nitrogen, sealed and placed in a constant temperature bath at 175C. for 2 hours. The resinous product was dissolved in toluene (50 ml.),and the product concentrated at a temperature of 60-70 C. at 20 mm. Hg.The resinous product (7.8 grams: an 85 percent conversion) was a waterwhite, clear resin having a molecular weight of approximately 14,000.

In a like manner, a fraction of the aromatic olefins recovered from thealiphatic solvent predominantly composed of indene can be used in thepreparation of desirable resins. For most purposes a fraction containinga minimum of about 85 weight percent indene forms preferred resinousproducts. These products can be prepared by the polymerizationtechniques previously described for the styrene concentrate.

We claim:

1. A process for the recovery of dicyclopentadiene from a feed streamcontaining from about to about 50 weight percent of dicyclopentadieneand from about 5 to about 50 weight percent of aromatic olefins andessentially free of components having a boiling point of C. or lowerwhich comprises contacting said stream with dimethyl sulfoxide in avolume ratio of the feed stream between about 1:1 and about 10:1 and anessentially saturated aliphatic solvent having a boiling point of lessthan about C. in a volume ratio of the feed stream of between about 2:1and 10:1 and recovering the dicyclopentadiene by distilling thealiphatic solvent therefrom.

2. The process of claim 1 wherein the dimethyl sulfoxide contains fromabout 2 to about 15 volume percent of water.

3. The process of claim 1 wherein the aliphatic solvent is ahydrocarbon.

4. The process of claim 1 wherein the aliphatic solvent is hexane.

5. The process of claim 1 wherein the ratio of feed stream to dimethylsulfoxide to aliphatic solvent is about 1:3:0.5.

6. The process of claim 1 wherein the feed stream is a dripolenefraction.

7. A process for the preparation of solid resinous products from a feedstream containing from about 5 to about 50 weight percentdicyclopentadiene and from about ,5 to about 50 weight percent ofaromatic olefins which comprises solvent extracting said stream withdimethyl sulfoxide and an aliphatic solvent having a boiling point ofless than about 140 C., recovering the aromatic olefins containing amaximum of about 3 weight percent dicyclopentadiene from the dimethylsulfoxide, polymerizing the aromatic olefins and recovering solidresinous product therefrom.

8. The process of claim 7 wherein the polymerization of the aromaticolefins is thermal.

9. The process of claim 7 wherein the polymerization of the aromaticolefins is performed in the presence of a Friedel-Crafts catalyst.

10. Processe of claim 9 wherein the Friedel Crafts catalyst is borontrifluoride.

11. The process of claim 7 wherein the polymerization of the aromaticolefins is performed in the presence of a free radical catalyst.

12. The process of claim 7 wherein the aromatic olefins recovered fromthe aliphatic solvent are distilled prior to the polymerization to afraction containing a minimum of about 90 weight percent styrene.

13. The process of claim 7 wherein the aromatic olefins recovered fromthe aliphatic solvent are distilled prior to the polymerization to afraction containing a minimum of about 85 weight percent indene.

References Cited UNITED STATES PATENTS 3,529,804 2/1969 Sze 208144 OTHERREFERENCES Chemical and Engineering News, Oct. 5, 1964 pp. 50-51.

Hydrocarbon Processing, vol. 45, No. 5 (1966), pp. 188-192.

Styrene, Its Polymers, Copolymers and Derivatives, ed. by Ray H. Boundyand Raymond F. Boyer, ACS, Monograph series, 1952, pp. 240-244 and252-254.

JOSEPH L. SCHOFER, Primary Examiner R. S. BENJAMIN, Assistant ExaminerUS. Cl. X.R.

Mum 3 @{3 5 80 7 W hated December 25, 1969 hw n lqrankfiggr dlglia andTakeo Hokama It is; m-rtifiml that error appears in the above-identifiedpatent and that said Lutu-rs l'ntont' an hereby corrected as shownbelow:

Col. 5, line 5%, in the table, under Example 1, Hexane Fraction, "51.2"should read --51.0--.

SIGNED AND SEALED JUL21197U SEAL) Attcst:

Edward M. Fletcher, It.

Atlesting Officer WILLIAM E. S-OIHUYLER, JR- Conmissioner of Patents

